What if Hiccup went selectively mute over the time he was hated on Berk to the point everyone minus Gobber thought he'd had an accident making him mute on top of that whenever he did speak it was as quiet as a whisper, and since Hiccup usually spends his time in the forge only Gobber knew Hiccup wasn't mute.
So instead of Hiccup saying that he hit Toothless with his contraption to his dad/Stoick he go's out by himself without anyone knowing where he is and what he's looking for and he finds Toothless eventually and they bond and Toothless actually treating Hiccup nicely and staying by him gets Hiccup to talk to him and it kinda goes as cannon exept Hiccup doesn't speak and it could go 4 ways that I can think of,
1. When being chosen to kill the Monstrous Nightmare we know as Hookfang Hiccup would run away successfully and free the dragons in the kill ring without getting caught and goes about life being a mini version of his mother by creating his own little sanctuary for dragons, freeing dragons from Hunters, Auctions, and Fighting rings and helping them adjust to a life of freedom of couse he would indeed run into dragon hunters, but of course Hiccup wouldn't talk to them and probably already learnt Dragonese and talks to the dragons earning him the title of a Demon from Helium.
2. Hiccup tries to runaway like in cannon but without Astrid and sees the nest with the Red Death and lands back on Berk, deciding he wanted to stop it but had his final exam in dragon training the next day and it goes as cannon with Stoic scaring Hookfang, Toothless saving Hiccup, and Hiccup stopping Toothless from Killing Stoic but instead of yelling he'd use some vibrations to tell him to stop. Instead of Hiccup letting slip that only a dragon can get to the nest someone of Berk uses there brain and thinks "what if we use the dragons to get to there home" and Hiccup runs towards the kill ring where the other dragons we know are and "tames" them getting the others on dragons and kills the red death, and throughout the years Hiccup would get more comfortable with talking to others but he'd mostly talk with the dragons. And he wouldn't have a crush on Astrid so he would tell or write that Astrid would be a better leader than him bc she's a great warrior, Viking, and she knows the people of Berk more. And Hiccup becomes the feral dragon boy who travels around sometimes with the gang and sometimes just with Toothless.
3. It would mostly go as cannon exept with Hiccup being sneaky and quiet up until the scean where he trains the others how to train there dragons where instead of talking to them giving comfort Hiccup just shows them it and wright's them the plan for defeating the Red Death instead of telling them on spot, Astrid would be the one to remind the group of the plan and they defeate the Red Death with the loss of Hiccup's left leg, and the crew would stick together like throughout the series, Hiccup being the main planner, but Astrid being the leader/2nd in comand giving the crew orders that Hiccup made.
4. Almost the same as 3 but Hiccup is perceived as a demon or witch by the Berkians for being able to talk after "loosing" his voice some would defend saying he just didn't talk but they wouldn't believe it and told Hiccup he couldn't come to Berk without being arrested, or killed along with Toothless so they leave Hiccup alone with Toothless, but of course some would secretly help him recover from loosing his leg with the Red Death, and he would again become a mini version if his mother finding her sooner due to there similar thinking about dragons they'd team up and take down Dragon Hunters, Auctions, and Fighting rings together, maybe they knew each other's identity earlier or later with working with each other to save dragons.
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Extra
For 3+4 if Astrid an Hiccup don't go on the romantic flight the thing that would stop her would he Hiccup talking to her, even if theu went on the romantic flight Hiccup talking to her would make her freeze bc everyone thinks he's mute but Gobber.
To communicate Hiccup would either write or sign nither he did often due yo him being ignored for being the runt of Berk along the dragon attacks no one talked to Hiccup a lot.
I'll make more posts fully explaining these turns in this au because I'm at ✨️Therapy✨️ and I need to share my thoughts 👍
